Now we are going to darken the texture using the Levels tool. Select the menu option Colors -> Levels. Now you'll see a window like the one shown in picture Colour levels window. To darken your image, increase the Output levels as shown in the example picture and press OK. At this moment your texture looks very dark.

Select the menu option Colors -> Invert and now your texture will look very bright, like the one shown in picture Bright texture.

Add a cloth layer

Displace map window

The next step is to add a cloth layer. For this tutorial I am going to use the Cloth texture explaind here Basic textures in GIMP: Cloth but you can use any cloth texture as a base)

Copy the Cloth texture as a new layer on top of the Bright texture image:

Open the Cloth texture in GIMP

Select the menu option Edit -> Copy

Go to the GIMP instance where you Bright texture is and select the menu option Edit -> Paste as and select New Layer from the drow down menu.

Note: To see and work with the different layers that you have in your image:

Select the menu option Windows -> Dockable Dialogs -> Layers '

This will open a window with the layers stack for your image as the one shown in picture Layers stack'

To work on one of the layers, select the corresponding layer in the stack and then work in GIMP main edition window: all you do (painting, erasing, resizing, etc) will be done on the selected layer.

To hide/show one of the layers, click on the eye icon at the left of each of the layers in the layer stack.